I usually just ride my bike near my home and the surrounding areas. But a few days ago I decided to venture a little further than the store and the bank. When I started down the road the speed limit sign said 50mph but when I got in 4th gear my bike struggled to reach 50. I have no idea why. This is the first time I've even attempted to go over 40(most places I go to don't require a higher speed). I checked my carb to see if it was dirty or clogged up but it wasn't. I checked the fuel line and vacuum line for clogs or tears but i found nothing. I checked to see if my carb was assembled correctly the last time I fiddled with it and everything was in it's correct place. I asked around and a few people told me it was the petcock and others​ said to change my air filter. (I haven't changed the air filter since I've owned the bike). Whenever I get pass 3/4th throttle in 4th gear the bike starts to putter and the engine feels like it just can't push it anymore. At one point when I was trying to reach 50mph the bike slowed down instead of going faster... Now I do need to adjust my throttle cable to take some of the free play out but I don't think that is the only culprit. Help?!?!

You should look at your diaphragm for leaks again.

If you don't smell fuel in the oil, and the oil level has not risen noticeably - the fuel may not have made it to the crankcase.

But - it might have made it to the air cleaner box.  It depends if the bike is parked on a slope which direction the gasoline will travel.